MONROVIA, Liberia — The four remaining patients infected during Liberia's recent string of Ebola cases have recovered, meaning there are currently no confirmed cases in the country though more than 100 people are still under surveillance, a health official said Friday.

"There are no Ebola cases anywhere in Liberia as we speak," Deputy Health Minister Tolbert Nyenswah told The Associated Press.

In an interview earlier with state media, he said the four patients had recovered and would be discharged in a ceremony on Monday.

"It is still too early to say is it is over," Nyenswah cautioned in the interview, noting that 123 contacts were being monitored.

Ebola killed more than 4,800 people in Liberia before the country was declared Ebola transmission-free on May 9. But in late June, a 17-year-old boy died from the disease. That transmission chain has produced five more cases, including the four patients Nyenswah said had been cured and a woman in her 20s who died earlier this week.

The cases originated in Nedowein, a community about 30 miles (48 kilometers) southeast of the capital, Monrovia. Samples taken from the 17-year-old boy show the virus is genetically similar to viruses that infected many people in the same area more than six months ago, the World Health Organization has said.

That finding by genetic sequencing suggests it is unlikely the virus was caught from travel to infected areas of Guinea or Sierra Leone, where the disease is hanging on, or from an animal, the organization said.

Liberia cannot be declared Ebola transmission-free again until it goes 42 days — twice the maximum incubation period — without any new cases.